Air-cooled blade for cutting plastic covers and the like from patterns



March 9, 1954 MlcHALEK 2,671,267

AIR-COOLED BLADE FOR CUTTING PLASTIC COVERS AND THE LIKE FROM PATTERNSFiled Sept. 15, 1951 M F V//////////////////,.-

V NTOR HARRY F.MICHALEK IIHIIIII E ATTORNEYS Patented Mar. 9, 1954 rorrrcs l'l'E AIR-'COGLED BLABE FGRCUTTINGPLASTIC .QOVERS AND THE LIKEFRQMPATTERNS Harry F. 'Michaiek, Ushlrosh, -Wis, assignor of one-half toAnton Michalek, Chicago, Ill.

My invention appertains to blades and more particularly to an air-cooledblade for an electrically driven, recip ocating knife utilized primarilyfor cutting p1 ic or cloth from patterns,

elongated teeth. .Still anotheriobjectof my invention is to form eachtooth with a longitudinally extendingcut- 2 ting edge parallel to thebase line of the blade with the two side edges of the tooth having afleam or bevel, providing a tooth of trapezoidal shape with three of itssides being cutting edges.

In the outing of lastics and also cloth, from 5 A salient feature of myinvention lies in the patterns, the pieces to be out are placed one uponfact that the two transverse side edges of one the other with thepattern outlined. An electooth are fieained or beveled to a sharpcutting t-rically driven reciprocating knife is then guided edge fromthe same side of the blade while the around the pat ern and the piecesare out .in actwo side edges of the next adjacent tooth are cordancetherewith. similarly beveled but from the opposite sid of Particularlyin the case of cutting plastic mathe blade, each adjacent toothalternating in a terials for the manufacture of furniture slip covlikemanner, whereby-the blade will not only preers, automotive seat coversand the like, the sent edges for both an up or down cutting movepiecesof plastic material generally placed merit, but the alternate side bevelof each-edge one hundred high and heretofore the knife blade will tendto stabilize the blade and aid it in used for following the pattern andcutting the cutting on the line. material has been of the straight edgetype. Due A further object of my invention is to provide primarily tothe rapid reciprocation of the knife, an air-cooled straight edge knifeof the above the blade and knife become unduly heated and character toeffectively out materials which in this tends to burn the knife and weldor fuse the the past could not be cut witha straight edge replasticsheets together making it most difficult ciprocatin knife. to cut on thepattern line. A still further object of my invention is to pro- Toovercome the above diiiiculties, it has been vide a simple, practicaland reliable construction the practice in the past to lubricate theknife and that is economical to manufacture, easy to asblade, usuallywith water. This procedure will semble and positive in its operation.With the out down the heat but it is quite unsatisfactory above andother objects in view, whichwill more in that it requires constantattention, and still .readilyappear as'the nature of my invention is isdifficult to follow the pattern line. Oftenbetter understood, thsameconsistsin the novel times, it is necessary for one man to exertpresconstruction, combination and arrangement of sure on a-tow ropeattached to the motor muuntparts hereinafter more fully described,illustrating, while a second man guides th blade in the ed and claimed.direction of cut. Serrated or sawing edges have A preferred practicalembodiment of my also been tried, but it has been found that thisinvention is shown in the accompanying drawtends to rip or tear thematerial rather than out ings, in which: it, and also leaves, inplastics, an undue accumu- Figure 1 is a side elevational view of myknife lation of dust or small particles, and, partlouand showing a bladeconstructed in accordance lariy, in cloth the edges so that with thepresent invention; the sewing machine operator an exceedingly Figure 2is a rear elevational view of my knife difficult time a neat attractiveapillustrating the uniform thickness of the knife pearing sea-in.Further, in the cutting of cloth 40 from the rear to the base line; frompatterns, a straight-edge knife could not be Figure 3 is a transversesection through my used at all, and most cloth is cut with a specialknife and blade, the section being taken on the round blade machine.line .3-3 of Figure l and looking in the direction Therefore, one of theprimary objects of my of the arrows: invention is to provide a novelair-cooled blade Figure 4 is atransverse sectional view through for astraight knife, which will cut plastic and my knife illustrating inparticular the bevel or cloth without the necessity of a liquidlubricant fieam of one of the teeth, the section'being taken and withouttearing, fusing or fraying the cut on th line 5- of Figure 1 and lookingin the edges of the material. direction of the arrows; 7

Another important object of my invention is to Figure 5 is a transversesectional view similar provide a straight edge knife in which the bladeto Figure 4, but illustrating the fieam or bevel of is beveled from thebase line at an equal angle the next adjacent tooth, the section beingtaken on both sides of the kniie, and formed with equalon the line E--of igure 1, and looking in the 1y spaced wide gullets extendingdownwardly direction of the arrows; from the cutting edge to the baseline, defining Figures is a fragmentary perspective view illustratingoneuse of mynovel knife, and showing it attached to its motor casing.

Referring to the drawings in detail,- wl'xerein similar referencecharacters designate corresponding parts throughout the several views,the letter A generally indicates a knife of the straight edge type, theblade II) of which is constructed in accordance with the teachings of mypresent invention. The knife A includes generally the blade I0, body IIand a slotted rear portion I2 which is adapted to be received in aclamping device of a motor M.

Referring in particular to Figure 1 of the drawings, it can be seen thatI provide a series of equally spaced gullets I3 of a generally arcuateshape at the base line It. The blade Ill, in its broad aspect, extendsfrom the base line I4 and terminates in a sharpened cutting edge I5. Asclearly shown, the cutting edge I5 is formed by beveling or sharpeningon an equal angle from both sides of the knife from the base lineupwardly, and the gullets I3 extend from the cutting edge I5 downwardlyto the base line I l as shown.

The spaced gullets define upstandin teeth I5, each tooth having anelongated cutting edge I! forming part of the longitudinally extendingcutting edge I5. The two transversely extending edges of each tooth I6are also fleamed or beveled to form sharp cutting edges I8 and I9. Thetwo side cutting edges I8 and I9 of one tooth are keenly sharpened orbeveled at the same angle from the same side of the blade, While the twoedges I8 and I9 of the next adjacent tooth are beveled at a similarangle but from the opposite side of the blade. This is illustrated quiteclearly in Figures 4 and 5 of the drawing in which similar sections aretaken through the knife, illustrating the cutting edges I8 of adjacentteeth.

The cutting edge I 8 of each tooth is utilized for cutting as the knifeis reciprocated upwardly. The cutting edge I9 of each tooth will cut asthe knife is reciprocated downwardly, and it is important to note thatas the alternate side cutting edges I8, I8 or I9, I9 are beveled fromopposite sides of the blade. It is primarily due to the above featurethat the knife and blade will be stabilized to cut in a straight lineenabling the knife to be easily guided about the pattern.

The space between the opposed cuttin edges I8, I9 which is provided bythe deep gullet I3 forms an air pocket, and during the rapidreciprocation of the knife II and blade II] the air will be rapidlymoved about the gullets I3 and cutting edges of the blade to cool thesame, thus preventing the knife or blade from burning. This isparticularly advantageous in the case of cutting plastic material as itwill eliminate the fusing of the cut edges without the necessity ofusing a liquid lubricant.

Attention should also be directed to the fact that in the preferredembodiment of my invention the transverse cutting edge I9 of one toothand the opposed cutting edge I8 of the next adjacent tooth extenddownwardly at an obtuse angle from the longitudinal cutting edge I! tomeet at the base line I4 in a slight arc. The cutting edges I'I, I9 andI9 are actually continuations and integral portions of the maincentrally disposed cutting edge I5.

For example, the cutting edge I! of one tooth lies in the samelongitudinal plane and extends longitudinally along the center of theknife with the cutting edge I! of the next adjacent tooth. The cuttingedge I8 of one tooth continues downwardly from the respective cuttingedge H on one side of the blade, crosses over at the base line I4 toextend upwardly from the opposite side of the 4 blade toward the nextadjacent cutting edge I! to form the opposed cutting edge I9.

While the knife and blade were primarily designed for cutting plasticseat covers, slip covers, etc., from patterns, I have found that theknife is also useful in a number of other art in which a straight edgeknife could not heretofore be used. For example, in Figure 6 of thedrawings, I have illustrated the knife II secured to its motor M andcutting a bale of cotton batting B. Previous to my invention, cottonbales could not be cut and were usually torn manually in 20" x 20"pieces, and it usually took a whole day for one man to tear three bales.By utilizing my knife in the manner illustrated in Figure 6 of thedrawing, it is possible to cut the bales of cotton with case.

In accordance with the illustrated method, I place the cotton bale Bupon a table T to which is resiliently clamped by means of a spring Sone end of a rod or pole 29. The pole 29 extends across the bale B andhas attached to its opposite end a foot stirrup 2| and flexible strap22, as shown. The operator merely places his foot in the stirrup 2I andapplies the desired pressure to the pole or rod 29 to hold the bale B tothe table T. The knife I I is then placed in the position shown and thecotton cut as desired. Not only do the gullets I3 provide a means forair to circulate about the blade and knife, but they also provide thenecessary side cutting edges to cooperate with the longitudinal cuttingedge.

In addition to cutting cotton, cloth and plastic, I have found that itworks equally as well in cutting paper for wrapping purposes, foamrubber, etc.

From the foregoing, it is believed that the features and advantages ofthe invention will be readily apparent to those skilled in the art, andit will, of course be understood that changes in the form, proportionand minor details of construction may be resorted to without departingfrom the spirit of the invention or the scope of the appended claim.

I claim:

A knife of the type to be secured to a motor mounting and rapidlyreciprocated comprising an elongated body having a longitudinallyextending blade, said blade including two parallel side faces and twobeveled faces, the intersection of said parallel side faces with saidbeveled faces defining a base line, each beveled face forming an equalangle at the base line with a respective parallel side face, saidbeveled faces intersecting to form a keen, centrally disposed cuttingedge, and a series of qually spaced elongated blade teeth defining widespaced gullets extending downwardly between two adjacent teeth from thecentrally disposed cutting edge and terminating at the base line, thegullet edges of one tooth being beveled from one side only to form keentransversely extending cutting edges, and the gullet edges of theadjacent teeth being beveled from the opposite side only with eachadjacent tooth being alternately beveled, said centrally disposedcutting edge co-inciding with the cutting edges of the elongated bladeteeth and forming one continuous cutting edge with the beveled sideedges of the teeth.

HARRY F. MICI-IALEK.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 1,227,234 Bacon May 22, 1917 1,246,905 Garlock et a1 Nov. 20,1917

